[Behavioral interactions and rhythms of activity of Glossina palpalis gambiensis and G. tachinoides (Diptera: Glossinidae) in a forest gallery in Burkina Faso].

Glossina palpalis gambiensis and G. tachinoides are the main vectors of human and animal trypanosomoses in West Africa. In some parts of their distribution area, they co-exist in sympatry, but little is known about their interactions.

Untreated human infections by Trypanosoma brucei gambiense are not 100% fatal.

The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years) of a cohort of 50 human African trypanosomiasis (HAT) patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis.

Trapping tsetse flies on water.

Riverine tsetse flies such as Glossina palpalis gambiensis and G. tachinoides are the vectors of human and animal trypanosomoses in West Africa. Despite intimate links between tsetse and water, to our knowledge there has never been any attempt to design trapping devices that would catch tsetse on water.

Diversity and spatial distribution of vectors and hosts of T. brucei gambiense in forest zones of, Southern Cameroon: epidemiological implications.

Host and vector distribution of Trypanosoma brucei gambiense was studied in relation to habitat types and seasons. Six (19.35%) of the 31 mammal species recorded in Bipindi were reservoir hosts.

Influence of habitat and seasonal variation on wild mammal diversity and distribution with special reference to the Trypanosoma brucei gambiense host-reservoir in Bipindi (Cameroon).

To evaluate the role of wildlife in the resurgence and perenisation of human African trypanosomiasis (HAT), we investigated the influence of habitat and seasonal variations on the diversity and spatial distribution of wild mammals, with special reference to those recognised as potential host-reservoirs of Trypanosoma brucei gambiense in Bipindi (southwestern Cameroon). To achieve this, we carried out transect surveys in four habitat types over two years. A total of 31 mammal species were recorded, of which 14 occurred in the undisturbed forest, 9 in cocoa plantations, 11 in farmlands and 11 in village-adjacent gallery forests.

[Distribution and ecology of the Savannah human African trypanosomiasis vectors in disturbed forest zone in south Cameroon: about case in the Doumé forest].

Vector control through trapping in the foci of humid forest areas is rather difficult because of the wide spreading of tsetse flies and transmission sites of human African trypanosomiasis. In fact, traps should be a priori set up everywhere to stop the transmission. The identification of the disease transmission sites enables efficient trapping through localisation of dangerous tsetse flies habitats needing vector control measures.

Wild fauna as a probable animal reservoir for Trypanosoma brucei gambiense in Cameroon.

In order to study the existence of a wild animal reservoir for Trypanosoma brucei gambiense in South Cameroon, blood was collected from wild animals in three human African trypanosomiasis foci and from a nonendemic control area. The 1142 wild animals sampled belonged to 36 different species pertaining to eight orders (407 primates, 347 artiodactyls, 265 rodents, 54 pangolins, 53 carnivores, 11 saurians and crocodilians, and five hyraxes). QBC and KIVI tests detected trypanosomes on 1.

Spontaneous cure of domestic pigs experimentally infected by Trypanosoma brucei gambiense. Implications for the control of sleeping sickness.

The existence of a pig reservoir for human African trypanosomosis (HAT) due to Trypanosoma brucei gambiense complicates the fight against this disease. This study, reports results obtained from pigs, which were inoculated with the blood of a person, suffering from HAT in Cameroon. The pigs were reared and kept in the shelter from all contact with Glossina, and monitored for 188 days.

Interest of tumor necrosis factor-alpha -308 G/A and interleukin-10 -592 C/A polymorphisms in human African trypanosomiasis.

This study aimed to determine whether single nucleotide polymorphisms (SNPs) within tumour necrosis factor-alpha (TNF) and interleukin-10 (IL10) promoters and genes are associated with human African trypanosomiasis (HAT). The polymorphisms used in the analysis were TNF(-308G/A), TNF(-238G/A), TNF(-1031T/C), TNF(+488G/A), IL10(-1082G/A) and IL10(-592C/A). A familial case-control sample of 277 individuals (102 cases and 175 parents) and a matched case-control group of 225 subjects (88 cases and 137 unrelated controls) were gathered together in this study.

Spatial and temporal patterns of human African trypanosomosis (HAT) transmission risk in the Bipindi focus, in the forest zone of southern Cameroon.

Vector control is an effective and cost-efficient way to disrupt the transmission of human African trypanosomosis (HAT); it has nonetheless been little used to date in the disease's foci. With the aim to target trapping more precisely and to develop an optimized vector control system, a transmission risk index was used in the HAT focus of Bipindi, in the forest zone of southern Cameroon. The authors used a simplified version of the index originally developed by Laveissière et al.

Infection rate of Trypanosoma brucei s.l., T. vivax, T. congolense "forest type", and T. simiae in small wild vertebrates in south Cameroon.

In order to identify the infection rate of trypanosome species infecting wild animals in four localities (Bipindi, Campo, Fontem and Nditam) of southern Cameroon, 1,141 wild animals were sampled. These animals belonged to 36 species grouped in 8 orders including 407 primates, 347 artiodactyls, 264 rodents, 54 pangolins, 53 small carnivores, 11 saurians and crocodilians and 5 hyraxes. PCR using specific primers for Trypanosoma vivax, T.

Characterization of Trypanosoma brucei s.l. infecting asymptomatic sleeping-sickness patients in Côte d'Ivoire: a new genetic group?

Six villagers in the Sinfra focus of sleeping sickness in Côte d'Ivoire who in 1995 were asymptomatic and refusing treatment, despite then being serologically and parasitologically positive for trypanosomes, were followed-up, while still refusing treatment, until 2002. In 2002, five of the six cases remained serologically positive but no trypanosomes could be found in any of them by use of the classical parasitological methods. A PCR-based assay, however, revealed that all six had the DNA of Trypanosoma brucei s.

Host age and time of exposure in Trypanosoma brucei gambiense Human African Trypanosomiasis.

Human African Trypanosomiasis is related to behavioural risk factors but complex interactions exist between (i) environmental and behavioural risk factors, (ii) vector and (iii) human host. Our aim was to investigate the interrelationships between previously analysed risk factors and the roles of age and time of exposure according to ethnic group and migration status. However, this descriptive and retrospective study is based on cases only (no controls) and our results must therefore be regarded as hypothesis-generating.

[Risk factors for human African trypanosomiasis in the Bipindi region of Cameroon].

In the course of two surveys carried out at the end of 1998 and beginning of 1999, sleeping sickness was diagnosed in a total of 43 people in the Bipindi region of Cameroon. This observation led us to investigate the mechanisms of transmission of human African trypanosomiasis in the epicentrer of the outbreak. A case-control study showed a particularly high risk of infection associated with hunting activities (Odds-Ratio: 2.

Diagnosis of human trypanosomiasis, due to Trypanosoma brucei gambiense in central Africa, by the polymerase chain reaction.

During a mass screening of sleeping sickness conducted in 1998 and 1999, and involving 27,932 persons in Cameroon and the Central African Republic, we tested the polymerase chain reaction (PCR) on whole blood for the diagnosis of human African trypanosomiasis due to Trypanosoma brucei gambiense. The 1858 samples obtained were from 4 groups: 155 infected patients, 1432 serological suspects detected by the card agglutination test for trypanosomiasis (CATT), 222 negative controls living in the prospected area (negative with the CATT and parasitological methods), and 49 negative controls (CATT and parasitological methods) and unexposed to the disease (Europeans). The technique of DNA extraction used made it possible to preserve the blood samples in the field.

Follow-up of Card Agglutination Trypanosomiasis Test (CATT) positive but apparently aparasitaemic individuals in Côte d'Ivoire: evidence for a complex and heterogeneous population.

The aetiological diagnosis of human African trypanosomiasis (HAT) is based on the detection of the parasite, but currently available parasitological tests have low sensitivity and are hampered by fluctuating parasitaemia. The identification of seropositive individuals on whom to focus parasitological examination is based on antibody detection by means of the Card Agglutination Trypanosomiasis Test (CATT/T.b.

[Spatial distribution and bloodmeal preferences of Glossina palpalis palpalis in the forest focus of Zoukougbeu (Ivory Coast). Epidemiological consequences].

In the sleeping sickness focus of Zoukougbeu (Côte d'Ivoire), in the cropping areas which are favourable for disease transmission, more than a quarter of the flies collected were found to have fed on domestic pigs. The sites where Glossina palpalis palpalis was caught fed on these animals were concordant with the sites where the patients were present. These results might indicate that in Zoukougbeu, but perhaps also in other sleeping sickness foci, the pig could play an active role in disease transmission, allowing the parasite to spread widely via the tsetse.

[Diversity of feeding behavior of Glossina palpalis palpalis in the forest belt of the Ivory Coast: relation to the prevalence of human African trypanosomiasis].

The feeding habits of Glossina palpalis palpalis, the main vector of human African trypanosomiasis (HAT) were retrospectively analysed using data collected between 1984 and 1994 in five areas in the forest belt in the mid-west of Côte d'Ivoire. The authors compare the feeding habits of the vector in these different foci. This analysis is aimed at determining if there is any relationship between the feeding pattern of tsetse-flies and the prevalence rates of HAT.

[Age group distribution of Glossina palpalis palpalis females in plantations and shallow water of the forest region of Côte d'Ivoire. Relation to the prevalence of sleeping sickness].

In epidemiologically dangerous biotopes of foci with high prevalence of Human African Trypanosomiasis (HAT), different female age groups (nulliparous, young parous, old parous) were observed in the same proportions. On the contrary, in areas without HAT or in low prevalence foci (< 0.2%), these proportions significantly differed.

[The focus of human trypanosomiasis in Campo (Cameroon). History and endemic situation in 1998].

For the first time in the last thirteen years, the human sleeping sickness focus at Campo, spanning the Cameroon-Equatorial Guinea border areas, has been prospected. The screening was carried out simultaneously on both sides of the border. This focus has been known since the beginning of the century but, contrary to what took place in other well-known foci in bordering countries south of Cameroon, either in the 1920s or the 1980s--there has never been an epidemic outbreak in that area.

[Incidence of African trypanosomiasis and the density of settlements in the forests of Côte d'Ivoire: the possibility of predicting high risk areas for surveillance of disease reservoirs].

In the forests of Côte d'Ivoire a surveillance network is needed to quickly and continuously detect cases of Human African Trypanosomiasis (HAT). This requires knowledge of high risk areas, and thus of an appropriate epidemiological indicator. Study of several HAT foci in Côte d'Ivoire shows a striking correlation between epidemiological risk and settlement density by square kilometer (r = 0983; P < 0.

[Detecting sleeping sickness: comparative efficacy of mobile teams and community health workers].

The solution to the problem of human African trypanosomiasis (HAT) first of all requires improved case detection. Effective tests have been available for a number of years but the results of medical surveys are still mediocre, mainly because the populations are poorly mobilized. Those few mobile teams still visiting villages obtain very low presentation rates.

[Epidemiologic risk of infectious disease transmission in regions of the Ivory Coast].

An epidemiological risk indicator based on purely entomological factors can be used to identify regions which are at higher risk of transmission within the endemic forest zones of Ivory Coast, and can serve to point out biotopes to be treated to make antivector campaigns more effective. In the forests of Ivory Coast, so-called socially open environments which are populated by a great number of ethnic groups who are highly mobile and whose amps are spread over a large area, are particularly vulnerable to epidemics of the disease. Transmission always occurs near water: at rivers, water holes, plantations.

A new method for identifying blood meals of human origin in tsetse flies.

A new sensitive technique using the electrophoresis of superoxide dismutase to distinguish between tsetse blood meals of human and non-human origin is described. In Côte d'Ivoire, 602 blood meals were collected; 170 were from man (28.3%), 377 from animals (62.